Update values of constants

[jkirk5]

Desired capability or behavior.

The constants.py file should be updated to use the following values for constants. Similar constants (that differ by code or with metric/english versions) will be replaced by a single value. The preference for constants is to use SI base units. We should use the openmdao unit conversion utilities to change to English units where needed. The source for the constants should be included as a comment for each entry. All other constants not mentioned in the list below should be removed.

Constants

GRAV_EARTH
Val: 9.80665
Units: m/s^2
Source: NIST (https://physics.nist.gov/cgi-bin/cuu/Value?gn|search_for=gravity)
Notes: A variable for gravitational acceleration needs to be added to the Aviary hierarchy and set in preprocessing based on which atmospheric model is being used.

GRAV_MARS
Val: 3.712
Units: m/s^2
Source: GRAM constants

GRAV_VENUS
Val: 8.87
Units: m/s^2
Source: GRAM constants

RADIUS_EARTH
Val: 6,371,009
Units: m
Source: GRS80, mean earth radius (rounded to nearest meter)
Notes: A variable for planetary radius needs to be added to the Aviary hierarchy and set in preprocessing based on which atmospheric model is being used.

RADIUS_MARS
Val: 3,386,200
Units: m
Source: GRAM constants, avg of equatorial and polar radii

RADIUS_VENUS
Val: 6,051,800
Units: m
Source: GRAM constants, avg of equatorial and polar radii

RHO_SEA_LEVEL
Notes: This will be addressed as part of issue #1191. For this issue, it can be kept as-is.

Suggested implementation.

No response

[jkirk5]

@ehariton can you copy the name of the source for planetary data GRAM mentions here? We should attribute the source to that rather than to GRAM

[ehariton]

GRAM data references NASA websites that no longer host the information :(

MARS:
Planetary constants (radius, gravity, etc.) are from the NASA Space Science Data Coordinated Archive Planetary Fact Sheet for Mars Web page:
https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html

VENUS:
Planetary constants (radius, gravity, etc.) are from the NASA Space Science Data Coordinated Archive Planetary Fact Sheet for Venus Web page: https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html.